This invention relates to fittings for attaching a metallic wire rope or structural strand end (both hereinafter referred to as a wire rope) to a support.
It is well known to provide a socket end fitting which is permanently anchored to the end of the rope by the latter being received within a through bore of the fitting with the strands of the rope preferably being spread within a divergent part of said bore, the end being secured therein by running molten solder spelter into the bore through the end remote from the main part of the rope, or by clamping the end of the wire rope within the fitting.
On mobile lifting and excavating equipment, one such type of equipment being a dragline, the ropes that extend between the A-frame and the mast and between the mast and the boom are usually attached to the structures (A-frame, mast and boom) by such a socket fitting. The constant change in the tension in the strands results in the wire rope oscillating up and down (and sideways to an extent). Since the socket fitting is so much heavier per unit length and stiffer than the wire rope, the wire rope will bend at the point where it exits the socket fitting. This will eventually lead to wire breakage and, ultimately, rope failure. To reduce the amount of wire breakage where the rope exits the socket fitting, the rope manufacturers have come up with a damper design which basically is a cylindrical piece of steel about several rope diameters in length that surrounds the wire rope and that is bolted to a flange on the socket fitting. In between the damper and the socket fitting is a non-metallic material that is like a thick soft gasket. The wire rope extends through the damper and the gasket before it enters the fitting. In theory, the gasket will compress to ‘damp’ the motion of the strands in the wire rope. This however has not been very successful in extending the useful life of the rope an appreciable amount.